Interferon and Ribavirin-Induced Oral Hyperpigmentation in Two Taiwanese Patients: Case Report and Literature Review

Abstract

Hyperpigmentation of the tongue and oral mucosa is a rare adverse event of the combination therapy with either interferon α (IFN) or polyethylene glycol-conjugated IFN (PEG-IFN) and ribavirin (RBV) in patients with hepatitis C virus (HCV) infection. The majority of these lesions either improves or resolves completely after completion of the therapy. It occurs more frequently in patients with dark skins and in female patients. While most patients have tongue hyperpigmentation alone, others also have hyperpigmentation involving gum, hard palate and/or buccal mucosa. It is not clear whether the hyperpigmentation of tongue and/or oral mucosa is associated with similar lesions in the gastrointestinal mucosa. We reported the first two cases of PEG-IFN and RBV combination therapy-induced oral hyperpigmentation in Taiwanese patients with hepatitis C, one in the tongue and the other in the buccal mucosa. Upper gastrointestinal (UGI) endoscopic exams revealed that none of these two patients had similar hyper-pigmented lesions in the esophageal, gastric, and duodenal mucosa. Since none of the previous reports mentioned any UGI endoscopic findings, further studies are necessary to determine whether the IFN or PEG-IFN and RBV-induced hyperpigmentation may also involve UGI mucosa. The mechanism of IFN and RBV-induced oral hyperpigmentation remains unclear. While most authors attributed oral hyperpigmentation to IFN or PEG-IFN, there has been no reported case of oral hyperpigmentation in patients treated with IFN, PEG-IFN or RBV alone. Therefore, it is more appropriate to call it IFN or PEG-IFN and RBV-induced oral hyperpigmentation.